Polar bears are badass. They have no fear of people, they know they're badass. I saw a show on Discovery, they take they people out in these giant vehicles to view them, picture an SUV thats twice a wide and about 15 feet tall, bars on all the windows. As soon as they stop moving, Polarbears just walk right up the vehicles, stand up and start trying to get into them. When it's time to move, or it get's too scary, the tour operators throw m80s out the window to scare the bears off. They just have no fear whatsoever.
edit:
here's what I'm talking about:
http://www.tundrabuggy.com/
Any other animals scoots at the sight of humans.